/**
 * @author aleeper / http://adamleeper.com/
 * @author mrdoob / http://mrdoob.com/
 * @author gero3 / https://github.com/gero3
 *
 * Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.
 *
 * Supports both binary and ASCII encoded files, with automatic detection of type.
 *
 * Limitations:
 *  Binary decoding supports "Magics" color format (http://en.wikipedia.org/wiki/STL_(file_format)#Color_in_binary_STL).
 *  There is perhaps some question as to how valid it is to always assume little-endian-ness.
 *  ASCII decoding assumes file is UTF-8. Seems to work for the examples...
 *
 * Usage:
 *  var loader = new THREE.STLLoader();
 *  loader.load( './models/stl/slotted_disk.stl', function ( geometry ) {
 *    scene.add( new THREE.Mesh( geometry ) );
 *  });
 *
 * For binary STLs geometry might contain colors for vertices. To use it:
 *  // use the same code to load STL as above
 *  if (geometry.hasColors) {
 *    material = new THREE.MeshPhongMaterial({ opacity: geometry.alpha, vertexColors: THREE.VertexColors });
 *  } else { .... }
 *  var mesh = new THREE.Mesh( geometry, material );
 */

if (window.requireNode) {
    try { 
        window.cSTLHelper = requireNode('cSTLHelper');
    } catch(e) {
        console.log("Platform doesn't support FLUX::cSTLHelper, fallback to js");
    }
}

THREE.STLLoader = function ( manager ) {

    this.manager = ( manager !== undefined ) ? manager : THREE.DefaultLoadingManager;

};

DataView.prototype.getUTF8String = function(offset, length) {
    var utf16 = new ArrayBuffer(length * 2);
    var utf16View = new Uint16Array(utf16);
    for (var i = 0; i < length; ++i) {
        utf16View[i] = this.getUint8(offset + i);
    }
    return String.fromCharCode.apply(null, utf16View);
};

THREE.STLLoader.prototype = {

    constructor: THREE.STLLoader,

    load: function ( url, onLoad, onProgress, onError ) {

        var scope = this;

        if (url instanceof ArrayBuffer) {
            console.log('start loading arraybuffer');

            try {
                onLoad( scope.parse( url ) );
            } catch(e) {
                onError("Failed to parse");
                throw e;
            }
        } else {
            var loader = new THREE.XHRLoader( scope.manager );
            loader.setResponseType( 'arraybuffer' );
            console.log('start loading stl url ', url.length);

            loader.load( url, function ( text ) {
                try{
                    onLoad( scope.parse( text ) );
                }catch(e){
                    onError("Failed to parse");
                    throw e;
                }
            }, onProgress, onError );
        }

    },

    parse: function ( data ) {

        var isBinary = function () {

            var expect, face_size, n_faces, reader;
            reader = new DataView( binData );
            face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
            n_faces = reader.getUint32( 80, true );
            expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

            if ( expect === reader.byteLength ) {

                return true;

            }

            // Support utf8 solid name.
            if(reader.getUTF8String(0,5) == 'solid' || reader.getUTF8String(1,5) == 'solid'){
                return false;
            }

            // some binary files will have different size from expected,
            // checking characters higher than ASCII to confirm is binary
            var fileLength = reader.byteLength;
            for ( var index = 0; index < fileLength; index ++ ) {

                if ( reader.getUint8( index, false ) > 127 ) {

                    return true;

                }

            }

            return false;

        };

        var binData = this.ensureBinary( data );

        return isBinary()
            ? this.parseBinary( binData )
            : this.parseASCII( this.ensureString( data ) );

    },

    parseBinary: function ( data ) {

        console.log("Start parsing binary");

        var reader = new DataView( data );
        var faces = reader.getUint32( 80, true );

        var r, g, b, hasColors = false, colors;
        var defaultR, defaultG, defaultB, alpha;

        // process STL header
        // check for default color in header ("COLOR=rgba" sequence).

        for ( var index = 0; index < 80 - 10; index ++ ) {

            if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

                hasColors = true;
                colors = new Float32Array( faces * 3 * 3 );

                defaultR = reader.getUint8( index + 6 ) / 255;
                defaultG = reader.getUint8( index + 7 ) / 255;
                defaultB = reader.getUint8( index + 8 ) / 255;
                alpha = reader.getUint8( index + 9 ) / 255;

            }

        }

        var dataOffset = 84;
        var faceLength = 12 * 4 + 2;

        var offset = 0;

        var geometry = new THREE.BufferGeometry();

        
        var vertices = new Float32Array( faces * 3 * 3 );
        var normals = new Float32Array( faces * 3 * 3 );

        if (window.cSTLHelper) {
            var result = window.cSTLHelper.parseStl(data, dataOffset, faces, vertices, normals);
        } else {
            vertices = new Float32Array( faces * 3 * 3 );
            normals = new Float32Array( faces * 3 * 3 );

            for ( var face = 0; face < faces; face ++ ) {

                var start = dataOffset + face * faceLength;
                var normalX = reader.getFloat32( start, true );
                var normalY = reader.getFloat32( start + 4, true );
                var normalZ = reader.getFloat32( start + 8, true );

                if ( hasColors ) {

                    var packedColor = reader.getUint16( start + 48, true );

                    if ( ( packedColor & 0x8000 ) === 0 ) {

                        // facet has its own unique color

                        r = ( packedColor & 0x1F ) / 31;
                        g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                        b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

                    } else {

                        r = defaultR;
                        g = defaultG;
                        b = defaultB;

                    }

                }

                for ( var i = 1; i <= 3; i ++ ) {

                    var vertexstart = start + i * 12;

                    vertices[ offset ] = reader.getFloat32( vertexstart, true );
                    vertices[ offset + 1 ] = reader.getFloat32( vertexstart + 4, true );
                    vertices[ offset + 2 ] = reader.getFloat32( vertexstart + 8, true );

                    normals[ offset ] = normalX;
                    normals[ offset + 1 ] = normalY;
                    normals[ offset + 2 ] = normalZ;

                    if ( hasColors ) {

                        colors[ offset ] = r;
                        colors[ offset + 1 ] = g;
                        colors[ offset + 2 ] = b;

                    }

                    offset += 3;

                }

            }
        }

        console.log("finished parsing");

        geometry.addAttribute( 'position', new THREE.BufferAttribute( vertices, 3 ) );
        geometry.addAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );

        if ( hasColors ) {

            geometry.addAttribute( 'color', new THREE.BufferAttribute( colors, 3 ) );
            geometry.hasColors = true;
            geometry.alpha = alpha;

        }

        console.log("added geometry");

        return geometry;

    },

    parseASCII: function ( data ) {

        console.log("Start parsing ascii");

        var geometry, length, normal, patternFace, patternNormal, patternVertex, result, text;
        geometry = new THREE.Geometry();
        patternFace = /facet([\s\S]*?)endfacet/g;

        while ( ( result = patternFace.exec( data ) ) !== null ) {

            text = result[ 0 ];
            patternNormal = /normal[\s]+([\-+]?[0-9]+\.?[0-9]*([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+/g;

            while ( ( result = patternNormal.exec( text ) ) !== null ) {

                normal = new THREE.Vector3( parseFloat( result[ 1 ] ), parseFloat( result[ 3 ] ), parseFloat( result[ 5 ] ) );

            }

            patternVertex = /vertex[\s]+([\-+]?[0-9]+\.?[0-9]*([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+/g;

            while ( ( result = patternVertex.exec( text ) ) !== null ) {

                geometry.vertices.push( new THREE.Vector3( parseFloat( result[ 1 ] ), parseFloat( result[ 3 ] ), parseFloat( result[ 5 ] ) ) );

            }

            length = geometry.vertices.length;

            geometry.faces.push( new THREE.Face3( length - 3, length - 2, length - 1, normal ) );

        }

        geometry.computeBoundingBox();
        geometry.computeBoundingSphere();

        return geometry;

    },

    ensureString: function ( buf ) {

        if ( typeof buf !== "string" ) {

            var array_buffer = new Uint8Array( buf );
            var strArray = [];
            for ( var i = 0; i < buf.byteLength; i ++ ) {

                strArray.push(String.fromCharCode( array_buffer[ i ] )); // implicitly assumes little-endian

            }
            return strArray.join('');

        } else {

            return buf;

        }

    },

    ensureBinary: function ( buf ) {

        if ( typeof buf === "string" ) {

            var array_buffer = new Uint8Array( buf.length );
            for ( var i = 0; i < buf.length; i ++ ) {

                array_buffer[ i ] = buf.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

            }
            return array_buffer.buffer || array_buffer;

        } else {

            return buf;

        }

    }

};

if ( typeof DataView === 'undefined' ) {

    DataView = function( buffer, byteOffset, byteLength ) {

        this.buffer = buffer;
        this.byteOffset = byteOffset || 0;
        this.byteLength = byteLength || buffer.byteLength || buffer.length;
        this._isString = typeof buffer === "string";

    };

    DataView.prototype = {

        _getCharCodes: function( buffer, start, length ) {

            start = start || 0;
            length = length || buffer.length;
            var end = start + length;
            var codes = [];
            for ( var i = start; i < end; i ++ ) {

                codes.push( buffer.charCodeAt( i ) & 0xff );

            }
            return codes;

        },

        _getBytes: function ( length, byteOffset, littleEndian ) {

            var result;

            // Handle the lack of endianness
            if ( littleEndian === undefined ) {

                littleEndian = this._littleEndian;

            }

            // Handle the lack of byteOffset
            if ( byteOffset === undefined ) {

                byteOffset = this.byteOffset;

            } else {

                byteOffset = this.byteOffset + byteOffset;

            }

            if ( length === undefined ) {

                length = this.byteLength - byteOffset;

            }

            // Error Checking
            if ( typeof byteOffset !== 'number' ) {

                throw new TypeError( 'DataView byteOffset is not a number' );

            }

            if ( length < 0 || byteOffset + length > this.byteLength ) {

                throw new Error( 'DataView length or (byteOffset+length) value is out of bounds' );

            }

            if ( this.isString ) {

                result = this._getCharCodes( this.buffer, byteOffset, byteOffset + length );

            } else {

                result = this.buffer.slice( byteOffset, byteOffset + length );

            }

            if ( ! littleEndian && length > 1 ) {

                if ( Array.isArray( result ) === false ) {

                    result = Array.prototype.slice.call( result );

                }

                result.reverse();

            }

            return result;

        },

        // Compatibility functions on a String Buffer

        getFloat64: function ( byteOffset, littleEndian ) {

            var b = this._getBytes( 8, byteOffset, littleEndian ),

                sign = 1 - ( 2 * ( b[ 7 ] >> 7 ) ),
                exponent = ( ( ( ( b[ 7 ] << 1 ) & 0xff ) << 3 ) | ( b[ 6 ] >> 4 ) ) - ( ( 1 << 10 ) - 1 ),

            // Binary operators such as | and << operate on 32 bit values, using + and Math.pow(2) instead
                mantissa = ( ( b[ 6 ] & 0x0f ) * Math.pow( 2, 48 ) ) + ( b[ 5 ] * Math.pow( 2, 40 ) ) + ( b[ 4 ] * Math.pow( 2, 32 ) ) +
                            ( b[ 3 ] * Math.pow( 2, 24 ) ) + ( b[ 2 ] * Math.pow( 2, 16 ) ) + ( b[ 1 ] * Math.pow( 2, 8 ) ) + b[ 0 ];

            if ( exponent === 1024 ) {

                if ( mantissa !== 0 ) {

                    return NaN;

                } else {

                    return sign * Infinity;

                }

            }

            if ( exponent === - 1023 ) {

                // Denormalized
                return sign * mantissa * Math.pow( 2, - 1022 - 52 );

            }

            return sign * ( 1 + mantissa * Math.pow( 2, - 52 ) ) * Math.pow( 2, exponent );

        },

        getFloat32: function ( byteOffset, littleEndian ) {

            var b = this._getBytes( 4, byteOffset, littleEndian ),

                sign = 1 - ( 2 * ( b[ 3 ] >> 7 ) ),
                exponent = ( ( ( b[ 3 ] << 1 ) & 0xff ) | ( b[ 2 ] >> 7 ) ) - 127,
                mantissa = ( ( b[ 2 ] & 0x7f ) << 16 ) | ( b[ 1 ] << 8 ) | b[ 0 ];

            if ( exponent === 128 ) {

                if ( mantissa !== 0 ) {

                    return NaN;

                } else {

                    return sign * Infinity;

                }

            }

            if ( exponent === - 127 ) {

                // Denormalized
                return sign * mantissa * Math.pow( 2, - 126 - 23 );

            }

            return sign * ( 1 + mantissa * Math.pow( 2, - 23 ) ) * Math.pow( 2, exponent );

        },

        getInt32: function ( byteOffset, littleEndian ) {

            var b = this._getBytes( 4, byteOffset, littleEndian );
            return ( b[ 3 ] << 24 ) | ( b[ 2 ] << 16 ) | ( b[ 1 ] << 8 ) | b[ 0 ];

        },

        getUint32: function ( byteOffset, littleEndian ) {

            return this.getInt32( byteOffset, littleEndian ) >>> 0;

        },

        getInt16: function ( byteOffset, littleEndian ) {

            return ( this.getUint16( byteOffset, littleEndian ) << 16 ) >> 16;

        },

        getUint16: function ( byteOffset, littleEndian ) {

            var b = this._getBytes( 2, byteOffset, littleEndian );
            return ( b[ 1 ] << 8 ) | b[ 0 ];

        },

        getInt8: function ( byteOffset ) {

            return ( this.getUint8( byteOffset ) << 24 ) >> 24;

        },

        getUint8: function ( byteOffset ) {

            return this._getBytes( 1, byteOffset )[ 0 ];

        }

     };

}
